1. Field of the Invention
This invention relates to an improved ebullated bed process. In the improved process hydrogen partial pressure is adjusted by adjusting total reactor pressure to achieve a selected 650.degree. F. minus yield. Individual component yields boiling below 650.degree. F. are also affected to different degrees.
2. Description of Other Relevant Methods in the Field
The ebullated bed process comprises the passing of concurrently flowing streams of liquids or slurries of liquids and solids and gas through a vertically cylindrical vessel containing catalyst. The catalyst is placed in random motion in the liquid and has a gross volume dispersed through the liquid medium greater than the volume of the mass when stationary. The ebullated bed process has found commercial application in the upgrading of heavy liquid hydrocarbons such as vacuum residuum or atmospheric residuum or converting coal to synthetic oils.
The ebullated bed process is generally described in U.S. Pat. Re. No. 25,770 issued Apr. 27, 1965 to E. S. Johanson. In Example 1, a residual hydrocarbon oil having a gravity of 8.3.degree. API is treated at a temperature of 830.degree. F., pressure of 3000 psig and hydrogen supplied at 1000 SCF H.sub.2 per barrel of charge stock, to yield a cracked product reduced in sulfur.
U.S. Pat. No. 3,412,010 to S. B. Alpert et al. discloses an ebullated bed process for the production of fuels such as diesel oil. A crude feedstock is passed to an ebullated bed at a temperature of 750.degree. F. to 900.degree. F., pressure of 1000 to 5000 psig with at least 2500 scf/bbl of hydrogen. It was found that with recycle, the yield of naphtha and furnace oil could be adjusted.
U.S. Pat. No. 3,681,231 to S. B. Alpert et al. describes an ebullated bed process wherein a petroleum residuum feed material is treated at a temperature of 600.degree. F. to 900.degree. F., a total pressure of 500 psig to 5000 psig and a hydrogen partial pressure in the range of from about 65% to 95% of the total pressure to yield fuel oils such as diesel oil.
U.S. Pat. No. 3,773,653 to G. Nongbri et al. discloses an ebullated bed process for the production of coker feedstocks. In the process a residuum feed is passed through an ebullated bed of particulate hydrotreating catalyst at a hydrogen partial pressure between 1500 and 3000 psi, temperature between 700.degree. F. and 900.degree. F. and space velocity between 0.3 and 1.5 volume of feed per hour per volume of reactor.